Chestnut plant named ‘AU Buck III’

ABSTRACT

‘AU Buck III’ is a new and distinct Chinese chestnut cultivar that is blight resistant, precocious and an annual bearer. It produces a medium to heavy crop load each year and a medium sized nut. Nut drop begins about September 25 and continues for a 4–5 week period. A large percentage of the nuts drop during the first three weeks of the period that nuts drop from this cultivar. ‘AU Buck III’ is a small to medium sized tree that is round in shape with low, dense, and spreading branches that was 6.71 meters tall, with a canopy covering an area of 41.85 square meters at 20 years old. ‘AU Buck III’ is the third cultivar to mature and drop nuts in a series of four Chinese chestnut cultivars that will provide for a continuous nut drop of a high energy wildlife food source from late August through mid-to-late November.

Latin name of the genus and species of the plant claimed: Castaneamollissima Blume.

Variety denomination: ‘AU Buck III’.

BACKGROUND OF THE INVENTION

A Chinese chestnut planting was established at Auburn University,Auburn, Ala., from nuts collected in China. The planting was establishedon the United States Department of Agriculture Horticulture Farm whichin later years became the Mainstation Horticulture Farm. Precocious andprolific-bearing, blight resistant seedlings were selected for nutappearance, size and quality. Each generation of seedlings were theproduct of controlled mass pollination from the most promising seedlingsselected from the previous generation. ‘AU Cropper’, ‘AU Leader’ and ‘AUHomestead’ were released from a second generation of approximately2000seedlings. A planting of third generation seedlings from controlledmass pollination of ‘AU Leader’, ‘AU Homestead’ and ‘AU Cropper’ wasestablished at the Auburn University Piedmont Substation at Camp Hill,Ala.

SUMMARY OF THE INVENTION

‘AU Buck III’ is from a sister line to ‘AU Leader,’ ‘AU Homestead’ and‘AU Cropper’.

The present invention relates to a new and distinct Chinese chestnutcultivar that is blight resistant, precocious, produces a heavy cropannually, average nut size is medium (10.9 g), and begins nut drop aboutSeptember 25 and continues for a 4–5 week period. A high percentage ofthe nuts produced drop during the first three weeks of the period thatnuts drop from this cultivar. Nut drop from ‘AU Buck III’ begins about 2weeks after nut drop from ‘AU Buck II’ begins. The medium sized nut isan excellent food source for wildlife such as deer and squirrels. The20-year old tree of ‘AU Buck III’ is a small to medium sized tree inheight that is 6.71 meters tall with a canopy of 7.29 meters wide andcovers a canopy area of 41.85 square meters. The ‘AU Buck III’ tree hasproduced a heavy crop load each season for tree size and produced 20.3kg (44.8 lbs) in 2006.

‘AU Buck III’ is the third cultivar to mature and drop nuts in a seriesof four Chinese chestnut cultivars that will provide for a continues nutdrop of a high energy wildlife food source from late August throughmid-to-late November. ‘AU Buck I’, ‘AU Buck II’ and ‘AU Buck IV’ are theother three cultivars, which are disclosed in U.S. patent applicationNo. 12/012,091, filed on Jan. 30, 2008, and entitled “Chestnut PlantNamed ‘AU Buck I’”, U.S. patent application No. 12/012,025, filed onJan. 30, 2008, and entitled “Chestnut Plant Named ‘AU Buck II’” and U.S.patent application No. 12/012,112, filed on Jan. 30, 2008, and entitled“Chestnut Plant Named ‘AU Buck IV’”, which are hereby incorporated byreference.

The new cultivar is able to be asexually reproduced by budding andgrafting onto a seedling Chinese chestnut rootstock. The uniquecharacteristics come true to form and are established and transmittedthrough asexual propagation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photograph of nuts of the ‘AU Buck III’ cultivar.

FIG. 2 is a photograph of nuts of the ‘AU Buck III’ cultivar.

FIG. 3 is a photograph of a tree of the ‘AU Buck III’ cultivar.

DETAILED BOTANICAL DESCRIPTION

The Chinese chestnut, Castanea mollissima Blume, is a cold hardytemperate zone species native to China. It can be grown between 30° and50° latitudes. The Chinese chestnut is resistant to chestnut blightfungus Cryphonectria parasitica. Generally, Chinese chestnuts are grownon a wide range of soils, but well-drained, deep and fertile soils areconsidered the best. Soils should be slightly acidic with pH 5.6–6.5.The name mollissima means soft hair and this species is recognized bydense hair on young leaves and downy yellow terminal parts of the shootsin winter. The leaf blade is thicker, and, in general, mature leaves arebroader than those of other species. The nuts have a small scar orhilum. The pellicle or thin membranous skin on the nuts is thin andpeels readily from the kernel. The trees are a spreading type andlong-lived with a round top. The trees have bark with furrows and budswith 3–4 scales and leaves are 2 ranked, serrated with numerous parallelveins.

Chestnuts are monoecious and staminate flowers appear on erectcylindrical catkins with 10–20 stamens and 6-parted calyx. Pistillateflowers are borne on lower part of the upper staminate catkins andrarely on separate catkins usually 3 in a prickly symmetrical involucrewith 7–9 styles and a 6-celled ovary. Nuts are small, brown with a palescar at the base. Generally, 1–3 nuts per involucre or bur are present.

‘AU Buck III’ is a small to medium sized tree that is round in shapewith low, dense, and spreading branches. The 20-year old tree is 6.71meters (22.0 feet) tall, with a trunk diameter at breast height of 22.6cm (8.90 inches). The canopy is 7.29 meters (23.90 feet) wide and coversan area of 41.85 square meters (450.48 square feet). The average nutweight is 10.9 g, average nut length is 28.4 mm (1.12 inches) and theaverage nut width is 30.4 cm (1.30 inches). The nuts start droppingabout September 25 and continue to drop for a 4 to 5 week period. A highpercent of the nuts produced drop during the first three weeks of theperiod that nuts drop from this cultivar. Nut drop from ‘AU Buck III’begins about 2 weeks after nut drop from ‘AU Buck II’ begins. ‘AU BuckIII’ is prolific and fruits annually.

In the planting at the Piedmont Substation, Camp Hill, Ala., accurateyields could not be obtained due to extremely heavy wildlife (deer andturkey) feeding. Therefore, the trees were rated for crop load eachyear. ‘AU Buck III’ has been a producer of a medium to large crop loadeach season. In the fall of 2006, individual trees were caged with 6foot (1.83 meters) tall chicken wire prior to nut drop to excludewildlife and nuts were picked up daily from the beginning throughcompletion of nut drop. The 20-year old ‘AU Buck III’ tree produced 20.3kg (44.8 pounds) of nuts in 2006. This yield is similar to reportedyields of similar aged trees.

The table below illustrates the specific differences between the ‘AUBUCK III’ cultivar and the ‘REVIVAL’ cultivar.

The botanical details of this new and distinctive variety of chestnuttree - with color definitions (except those in common color terms)referenced to Royal Horticultural Society's Colour Chart (RHS) and colorwas also determined using an electronic spectrophotometer to determinehue angle and Chroma (spectrophotometer model CM-2002; Minolta CameraCo., Japan). ‘AU BUCK III’ CHESTNUT Tree: Size (at maturity) - small -twenty year old original tree is 6.71 meters tall with a canopy width of7.29 meters and a canopy area of 41.85 sq. meters Tree shape is round.Vigor - very vigorous Trunk: Form - upright with branches low and denseTexture - relatively smooth Color of bark - brown RHS N200A, Chroma C*11.29, hue angle 80.74 Branches: Form - spreading Texture - relativelysmooth Lenticels - few, small Branching habit - low and dense Color -new wood: brown, RHS 200C, Chroma C* 16.06, hue angle 68.53, maturewood: grey-brown RHS N199A Chroma C* 13.18, hue angle 88.29 Foliage:Quantity - abundant Density - dense Leaves: Size - large. Length (cm)19.3 (16.1-22.1) [20] width (cm) 7.7 (5.0-9.5) [20] leaf ratio 2.6(2.2-3.4) [20] Shape - oblong-elliptic leaf tip - acute to occasionallyacuminate leaf base - cuneate to rounded; equal, rarely obliqueThickness - thick. Leaf venation 1° pinnate: 2° parallel, stronglyprominent abaxially Texture - strongly coriaceous Margin - coarselyserrate; teeth spreading, ascending Petiole - length 1.4 cm (0.9-2.1)[20] Petiole pubescence - mixed stellate and simple hairs Color- adaxialsurface, glabrous blade; simple and stellate hairs on main veins mediumto dark green; very shiny, RHS 147A, Chroma C* 16.23, hue angle 117.35abaxial surface, densely stellate hairs mixed with occasional longstraight hairs on blade, long simple hairs on main veins, RHS 147B,Chroma C* 21.68, hue angle 103.78 Bloom: Amount of bloom - heavy Color -at anthesis, 161D greyed-yellow group, 157D green-white group, 155Cwhite group Blooming period - mid-May. After foliation in April. Age atwhich tree starts flowering - early, 2-3 years after graft replacement.Male flower - Catkin length (cm) - 14.0 (9.6-19.8) [10] Male flower -stamen number per catkin - 10.8 (8.13) [10] Female flower - flowernumber per bur - 3 Female flower - style number per flower 7.7 (7-8) [3]Crop: Bearing - regular annual bearer Productivity - prolific Ripeningperiod - long, nuts begin dropping about September 25 and continues fora 4-5 week period. Distribution of nuts on tree - well distributed,fruits on terminals with 2-4 burs per terminal. Tenacity - burs crackwhile on tree and nuts release and drop from bur. Hull: Description -spiny round bur Size - 2.34-2.56″ in diameter Number of nuts - 2-3 perbur Dehiscence - splits easily when still on tree Color - yellow-greenat dehiscence, RHS N144C Nut: Size -medium; average size- 1.12″ × 1.30″× 0.71″. Average weight - 10.9 grams 42 (36-46) nuts per pound. Form -flattened on 1 side, occ. 2, hemispheric on the other side, Blossomend - small obtuse tip Basal end - broadly rounded Color - brown,lustrous RHS 200B, Chroma C* 11.58, hue angle 36.17 Pubescence- mixedlong and short, fine, white hairs densely covering ¼ of the distal end,otherwise very sparse to glabrous elsewhere Shell - thin Hardness ofshell - relatively hard, yet not rigid Texture of shell - smoothPercentage of kernel to nut - very high-90-95% Kernel: Size - almost aslarge as nut size Form - same as nut shape Pellicle - thin Flavor -excellent, very sweet Color - straw color, RHS 152D, Chroma C* 48.19,hue angle 81.90 Resistance to insects: no unusual susceptibilities notedResistance to disease: no susceptibilities to disease noted The chestnuttree and its nuts herein described may vary in slight detail due toclimatic and soil conditions under which the variety may be grown; thepresent description being of the variety as grown in Camp Hill, Ala. Thebotanical details of this variety of chestnut tree - with colordefinitions (except those in common color terms) referenced to Maerz andPaul Dictionary of Color - are as follows: ‘REVIVAL’ Tree: Size (atmaturity) - large Vigor - very vigorous Trunk: Form - upright withbranches spreading in upper reaches of tree. Texture - relatively smoothColor of bark - Silvergray (13-A-1) Branches: Form - strong Texture -relatively smooth Lenticels - few, small Branching habit - spreading inupper region of tree Color - new wood: reddish brown and glossy, maturewood: silver gray Foliage: Quantity - abundant Density - dense Leaves:Size - large. Average length - 5-7″ (including petiole). Average width -2″ Shape - oblong with acute tip and rounded base Thickness - thickTexture - smooth Margin - dentate Petiole - length: medium. Thickness:medium. Color - Top side - glossy dark green (22-L-12). Under side -lighter green (21-D-7). Bloom: Amount of bloom - heavy Color - creamwhite (17-B-1) Blooming period - late. After leaf out in April Age atwhich tree starts flowering - early; 2-3 years years after graftreplacement. Crop: Bearing - regular (yearly) bearer Productivity -prolific Ripening period - short. September 15-October 1. Distributionof nuts on tree - well distributed Tenacity - burrs crack while on treeand nuts easily release, many falling by themselves Hull: Description -spiny, round burr Size - 3-4″ in diameter Number of nuts - 2-3 per burrDehiscence - splits easily when still on tree. Some entire burrs splitand fall to ground Color - brown (15-A-8) Nut: Size-large. Averagesize - 1⅛″ × 1⅛″ × 1″ thick, Average weight - 24-32 nuts per poundForm - broad and ovoid on one side, flat on other side Blossom end -pointed tip Basal end - flattened Color - India Red (7-L-6). Shell -thin Hardness of shell - relatively hard, yet not rigid Texture ofshell - smooth Percentage of kernel to nut - very high (95%) Kernel:Size - almost as large as nut size Form - same as nut shape Pellicle -thin Flavor - excellent. Very sweet. Color - Oyster white (10-B-1)Resistance to insects: no unusual susceptibilities noted Resistance todisease: very high inherent resistance to chestnut bark fungus (Endothiaparastica), no other susceptibilities to any other disease The chestnuttree and its nuts herein described may vary in slight detail due toclimatic and soil conditions under which the variety may be grown; thepresent description being of the variety as grown in Alachua, Fla.

‘AU Buck III’ is different from ‘AU Gobbler I’ in several ways. Forexample, the size of the trees, the trunk forms and colors, thebranches, the leaves, the crop and the nuts have differences.Specifically, the ‘AU Buck III’ tree is shorter with a canopy areasmaller than the ‘AU Gobbler I’ tree. The ‘AU Buck III’ branches arespreading and brown (new) or grey-brown (mature); whereas, the ‘AUGobbler I’ branches are upright and brown (new) or greyed-green(mature). The leaves differ in size, petiole and color. The ripeningperiod for the ‘AU Buck III’ is around September 25 and continues for a4–5 week period, but the ‘AU Gobbler I’ ripening period is around August25 and continues for 4–5 weeks. The average weight of the nuts of ‘AUBuck III’ is 10.9 grams versus 7.7 grams for ‘AU Gobbler I’.Furthermore, ‘AU Buck III’ has roughly 42 nuts per pound, and ‘AUGobbler I’ has roughly 59 nuts per pound.

‘AU Buck III’ is different from ‘AU Gobbler II’ in several ways. Forexample, the trees, the trunk colors, the branch colors, the leaves, thecrop and the nuts have differences. Specifically, the ‘AU Buck III’ treeis shorter with a canopy width and canopy area smaller than the ‘AUGobbler II’ tree. The ‘AU Buck III’ branches are brown (new) orgrey-brown (mature); whereas, the ‘AU Gobbler II’ branches are brown(new) or greyed-green (mature). The leaves differ in size, shape andcolor. The ripening period for the ‘AU Buck III’ is around September 25and continues for a 4–5 week period, but the ‘AU Gobbler II’ ripeningperiod is around September 5 and continues for 4–5 weeks. The averageweight of the nuts of ‘AU Buck III’ is 10.9 grams versus 5.7 grams for‘AU Gobbler II’. Furthermore, ‘AU Buck III’ has roughly 42 nuts perpound, and ‘AU Gobbler II’ has roughly 65–101 nuts per pound.

‘AU Buck III’ is different from ‘AU Premier’ in several ways. Forexample, the trees, the trunk colors, the branch colors, the leaves, thecrop and the nuts have differences. Specifically, the ‘AU Buck III’ treeis taller with a canopy width and canopy area larger than the ‘AUPremier’ tree. The ‘AU Buck III’ has a brown trunk, and the ‘AU Premier’has a greyed-green trunk. The ‘AU Buck III’ branches are brown (new) orgrey-brown (mature); whereas, the ‘AU Premier’ branches are brown (new)or greyed-green (mature). The leaves differ in size, shape, thickness,texture, petiole and color. The ripening period for the ‘AU Buck III’ isaround September 25, and the ‘AU Premier’ ripening period is earlySeptember through mid-November. The average weight of the nuts of ‘AUBuck III’ is 10.9 grams versus 1.26 grams for ‘AU Premier’. Furthermore,‘AU Buck III’ has roughly 42 nuts per pound, and ‘AU Premier’ hasroughly 360.3 nuts per pound.

‘AU Buck III’ is different from ‘AU Encore’ in several ways. Forexample, the trees, the trunk colors, the branch colors, the leaves, thecrop and the nuts have differences. Specifically, the ‘AU Buck III’ treeis taller with a canopy width larger than the ‘AU Encore’ tree. The ‘AUBuck III’ has a brown trunk, and the ‘AU Encore’ has a greyed-greentrunk. The ‘AU Buck III’ branches are brown (new) or grey-brown(mature); whereas, the ‘AU Encore’ branches are brown (new) orgreyed-green (mature). The leaves differ in size, thickness, texture,margin, petiole and color. The ripening period for the ‘AU Buck III’ isaround September 25, but the ‘AU Encore’ ripening period is lateSeptember through late November. The average weight of the nuts of ‘AUBuck III’ is 10.9 grams versus 2.4 grams for ‘AU Encore’. Furthermore,‘AU Buck III’ has roughly 42 nuts per pound, and ‘AU Encore’ has roughly189.2 nuts per pound.

1. A new and distinct cultivar of the species Castanea mollissima Blumenamed ‘AU Buck III’ as described and illustrated herein.